Xiaomi Mi 8
MIUI 14
battery degradation
Mi 8
In this article, you'll find 5 working diagnostic methods, from hidden engineering menus to third-party applications, we'll look at how to find out the real capacity, wear and tear level, and even predict the remaining life, and at the end, a checklist of actions if the battery is already "dying."
Important: The Mi 8 is equipped with a 3400 mAh LB4377 non-removable battery (typical) and after 500-800 charge cycles, its capacity can drop to 70-80% of the original one, which is normal, but requires adjustments in usage habits.
1. Check through the engineering menu (#4636##)
The fastest way to get basic battery information is to use Android’s hidden engineering menu, which is available without root rights or additional apps.
Instructions:
- Open the Phone app.
- Enter the combination: ##4636###.
- In the menu that appears, select Battery Information.
Here you will see the key parameters:
- 🔋 Level of charge (level) - current percentage in numbers.
- 🔌 Power source: battery (from battery) or usb (when charging).
- 🌡️ Temperature: in tenths of a degree Celsius (for example, 285 = 28.5°C).
- ⚡ Voltage – should be in the range of 3.7-4.2 V at 100% charge.
⚠️ Note: If the full charge voltage is below 4.0V, it is a sign of severe wear or malfunction of the controller.°C in normal use, they talk about overheating.
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Write down the voltage at 100%, 50% and 10% charge, and the difference between them will help you assess the degree of degradation: the new battery has a smooth voltage drop, the worn one has a sharp one.
2.Use of the AccuBattery application
AccuBattery is one of the most accurate applications for monitoring battery health, analyzing charging cycles, measuring actual capacity and predicting wear and tear, and you can download it for free on Google Play.
How to use:
- 📱 Install and open the application.
- 🔄 Wait. 2-3 full charge cycles (from 0% before 100%) calibration.
- 📊 Go to the Health tab – here you will see the percentage of wear and tear.
- 📉 In the Charging tab, see the Charging Speed Graph – sudden jumps may indicate problems with the cable or adapter.
Example of data interpretation:
| Indicator. | Norma. | Warning | Critically. |
|---|---|---|---|
| Capacity | 2800–3400 mAh | 2200-2800 mAh | <2200 mAh |
| Wearing | <20% | 20–40% | >40% |
| Temperature during charging | <35°C | 35–40°C | >40°C |
| Discharge speed in plainness | <1%/hour | 1-3%/hour | >3%/hour |
⚠️ Note: If AccuBattery shows capacity below 2500 mAh, battery needs to be replaced. 30% The time of autonomous work is significantly reduced, and 50% And above the smartphone can be turned off when 30-40% charge.
Calibrate the battery (discharge to 0% and charge to 100% without interruptions)
Check the temperature during charging
Use the original adapter (18W for Mi 8)
Limit fast charging in MIUI settings
Reset the settings to factory (if wear appeared after the update)-->
3.Analysis through ADB (for advanced users)
If you want the most accurate battery data, including the number of charging cycles and factory capacity, use the battery. ADB-This method requires connecting the smartphone to a PC.
Instructions:
- Download and install Platform Tools (includes adb).
- Enable USB Debugging in the Developer Settings (Settings → About Phone → MIUI Version – Press 7 times, then return to Additional → For Developers).
- Connect the Mi 8 to your PC and type in the command line: adb shell dumpsys battery
In conclusion, pay attention to the parameters:
- Capacity - current capacity in mAh (may differ from passport).
- cycle_count — Number of complete charging cycles (norm to 500).
- Health – state: GOOD, FAIR, POOR, etc.
- Technology: A type of battery (should be Li-ion or Li-poly).
⚠️ Attention: If health shows DEAD or OVERHEAT, The battery is defective and needs urgent replacement. cycle_count higher 800 speaks of extreme wear.
What if the ADB does not recognize the device?
4. Discharge test (method "100 to 0%")
It takes time, but it doesn't require software, and it helps you estimate the actual battery life and detect percentage spikes (a symptom of downed calibration).
How to run the test:
- Charge your smartphone to 100% and disconnect from the network.
- Use it in normal mode (no games and heavy tasks), fixing the time.
- See how long it takes to get it out before it's automatically shut down.
Standards for Xiaomi Mi 8 (at an average load):
- 📞 Calls/social media: 8-12 hours.
- 🎮 Games: 3-5 hours.
- 📷 Video shooting: 4-6 hours.
- 🌙 Standby (no activity): 1.5–2 days.
If battery life is reduced by 30% or more, the battery is worn out.
- 🔄 Sharp percentage jumps (for example, from 30% to 1% per minute) – a sign of a downgraded calibration.
- 🔥 Overheating during discharge - wear or short circuit is possible.
- ⚡ Spontaneous reboot at 10-30% - the battery does not hold voltage.
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If the smartphone turns off at 20 to 30 percent charge, but after charging, it shows 0%, it's not a software failure, it's a physical wear and tear of the battery. Calibration won't help, you need to replace it.
5. Visual examination and physical diagnosis
Sometimes the problem is not the software, but the physical state of the battery. If you're ready to disassemble your smartphone, check the battery for:
- 🔍 Bloating - warping of the body or detachment of the display.
- 💧 Electrolyte dashing (white plaque on the board).
- 🔌 Oxidation of contacts (green or black coating).
- 🔥 Traces of overheating (darkening, melting).
⚠️ Attention: If the battery is swelling, immediately turn off the smartphone and do not use it. The risk of fire or explosion when mechanically exposed is extremely high. The bloated battery cannot be pierced, bent or thrown into the trash can - it must be disposed of in special reception points.
For the inspection, you will need:
- 🛠️ Plastic shoulder blade (mediator).
- 🔧 Screwdriver. T3 or T4 (Mi 8 screws).
- 🧲 Suction cup for removing the display (optional).
If you are not sure about your skills, it is better to contact the service center.The cost of replacing the battery with Xiaomi Mi 8 in 2026 is 1500-2500 rubles (depending on the quality of the battery and the region).
What to do if the battery is worn out?
If the diagnosis has shown critical wear, there are several ways to solve:
Battery calibration (helps only when the controller fails):
- Discharge the smartphone before automatically shutting down.
- Connect to the original charger and charge up to 100% without interruptions (at least 3 hours).
- Turn off and turn on your smartphone again. Repeat the cycle 2-3 times.
Optimization of consumption:
- 🔄 Turn off Auto Brightness and set a fixed value (40–60%).
- 📵 Limit the background activity of applications in Settings → Battery → Optimization.
- 📶 Use Power Saving Mode (turns on at 15% charge).
- 🔌 Charge your smartphone up to 80% (extends service life by 20-30%).
Battery replacement:
- 🏠 Xiaomi’s official service is a 6-month warranty, but a high price.
- 🛠️ Unofficial workshops are cheaper, but the risk of poor-quality battery.
- 🔧 Self-replacement - only if you have experience (a soldering iron is required to detach the plume).
⚠️ Note: When replacing the battery with the Mi 8, be sure to check:
- 🔋 Capacity of the new battery (must be at least 3300 mAh).
- 🔌 Compatibility of controller (some cheap batteries do not support fast charging).
- 🛡️ Protection against overheating (the body must be marked) PTC or Protection Circuit).